GLPHubglpresearchhub.com
Read-only archive. GLP Research Hub is a static community record — nothing here is for sale, no account is needed, and no vote you cast is counted. Why?
Single comment threadYou are looking at one branch of gradient — 17 things I got wrong before I got it right — 57 comments in the full submission. View in context.
1.5k
c/hplc·submitted 2 years ago by u/ravi_bergstrom

gradient — 17 things I got wrong before I got it right

Explainerbranch of 6 comments

gradient — 17 things I got wrong before I got it right. I have gone back and forth on this for months. Gave the same trace to two people I trust and got two integrations about a point apart. That was the most educational afternoon I have had here. Carryover from a previous high-concentration injection looks exactly…

Read the full submission and all 57 comments →

This branch

6 comments, started 2 years ago
u/peak_area_peteMOD68 points·2 years ago

Method questions stay here; supplier claims go to c/vendorvetting with a document attached.

replysharereportpermalink
u/egfr_watcher54 points·2 years ago·edited

What did system suitability look like on that sequence?

replysharereportpermalink
u/two_mil_or_one47 points·2 years ago

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the purity figure is unanchored.

replysharereportpermalink
u/fatima_yildiz13 points·2 years ago

Cosigning the wavelength point. Half the disagreements in this board are two people looking at different detectors.

replysharereportpermalink
u/ravi_bergstromOP42 points·2 years ago·edited

Correction: that is a tailing factor, not a plate count. Different diagnostics for different problems.

replysharereportpermalink
[removed]31 points·2 years ago

[removed by moderator]

replysharereportpermalink

← back to the whole thread

About c/hplc

The analytical deep end: RP-HPLC methods, gradient design, integration decisions, LC-MS confirmation, amino-acid analysis, water content, and why two labs can report 98.1% and 96.4% on the same vial and both be right. Post the chromatogram, not the summary line.

32kmembers
130submissions
Sep 2023created
submissions / month, last year
Sponsored

Sigma-Aldrich Standards

Certified reference materials for peptide identity and purity work.

sigmaaldrich.com
More in c/hplc
c/hplc rules
  1. Chromatogram or it did not happen. Axis labels included.
  2. State the method: column, gradient, detection wavelength, injection volume.
  3. Area% is not mass%. Posts that conflate them get a correction flair, not a removal.
  4. Independent community. Nobody here sells anything, and anyone who tries is banned.
  5. Not medical advice. Describe what you did; never prescribe to a stranger.
  6. Claims need evidence. Batch numbers, dated screenshots, independent test reports, or a citation.
  7. No referral links, discount codes or affiliate URLs. Permanent ban, no appeal.
  8. No contact handles, wallet addresses or tracking numbers — they identify people.
  9. Be recognisably decent. Disagree hard, insult nobody.
Full rules and how they are enforced →
Moderators
u/sig_figs_samu/hplc_hobbyistu/peak_area_peteu/mass_spec_maggie
Volunteers. Unpaid, unaffiliated, and reachable through modmail only.
Before you read on

Several compounds discussed on GLP Research Hub are sold for research use only and are not approved for human use anywhere. Nothing here is medical advice and none of it is written by your clinician. If a post reads like an instruction, treat it as a description of what one stranger did.

Full disclaimer →